Production of tetraalkylstilbene quinones and tetraalkoxystilbene quinones



Patented Apr. 22, 1 952 PRODUCTION OF TETnAA KYLsTILBENE QUINONES AND TETRAALKOXYSTIL- BENE QUINONES William K. T. Gleim, Orland Park, Alexander Gaydasch, Brookfield, and Robert H Rosenwald, Western Springs, 111., assignors to Universal Oil Products Company, Chicago, 111., a corporation of Delaware No Drawing. Application June 17, 1950, Serial No. 168,846

This invention relates to a process for preparing tetraalkylstilbene quinones and tetraalkoxystilbene quinones. More particularly, this inven tion relates to a process for preparing tetraalkylstilbene quinones and tetraalkoxystilbene quinones in which each alkyl and alkoxy group contains from one to six carbon atoms.

An object of this invention is to produce an organic compound selected from the members of the group consisting of a tetraalkylstilbene quinone and a tetraalkoxystilbene quinone.

Another object of this invention is to produce a 3,5,3',5'-tetraalkylstilbene quinone.

Still another object of this invention is to produce a 3,5,3',5'-tetraalkoxysti1bene quinone.

An additional object of this invention is to produce 3,5,3,5-tetra-tert-butyl-stilbene quinone.

Still another object of this invention is to produce 3,5,3,5-tctramethyl-stilbene quinone.

One embodiment of this invention relates to a process for producing a tetra-substituted stilbene quinone in which the substituents are selected from the members of the group consisting of an alkyl group and an alkoxy group each containing from one to six carbon atoms which comprises oxidizing a member of the group consisting of a dialkyl-p-cresol and a dialkoxyl-p-cresol having alkyl and alkoxyl groups containing from one to six carbon atoms.

Another embodiment of this invention relates to a process for producing a polyalkylstilbene quinone which comprises oxidizing a polyalkylphenol in which the alkyl groups contain from one to six carbon atoms.

Still another embodiment of this invention relates to a process for producing a tetra-alkylstilbene quinone which comprises oxidizing a 2,6-dialkyl-p-cresol having alkyl groups containin from one to six carbon atoms.

A further embodiment of this invention relates to a process for producing tetramethylstilbene quinone which comprises oxidizing 2,6-dimethylp-cresol.

A still further embodiment of this invention relates to a process for producing tetra-tert-butylstilbene quinone which comprises oxidizing 2,6- di-tert-butyl-p-cresol.

We have found that 2,6-dialkyl-p-cresol and 2,6-dialkoxy-p-cresol which have from one to six carbon atoms in said alkyl and alkoxyl groups can be oxidized readily to form certain tetraalkyl-stilbene quinones and tetra-alkoxy-stilbene 12 Claims. (Cl. 260-396) quinones which may be represented by the equation:

in which It represents a member of the group consisting of an alkyl group and an alkoxyl group having from one to six carbon atoms.

We have oxidized 2,6-dialkyl-p-cresol by different means including use of alkali metal ch10- rates; ferricyanides-lead dioxide, silver oxide,'and the like, to produce tetraalkylstilbene quinones. Such an oxidation is carried out, for example, by heating a 2,6-dialkyl-p-cresol at a temperature of from about 20 to about C. with sodium chlorate and an aqueous solution containing sulfuric acid or another mineral acid.

In another method of effecting such an oxidation, a pentane solution of a 2,6-dialkyl-p-cresol is contacted with an aqueous solution containing 10% by weight of sodium hydroxide and then this mixture is stirred While an aqueous solution of potassium ferricyanide is added thereto to form a tetraalkylstilbene quinone.

Similar oxidation treatment of a 2,6-dia1koxyp-cresol produces a tetraalkoxystilbene quinone.

These 2,6-dialkyl-p-creso1 and 2,6-dialkoxy-pcresols are also referred to as 2,6-dialky1-4- methyl phenols and 2,6-di-alkoxy-4-methylphenols.

Tetra-alkylstilbene quinones and tetra-alkoxy-i stilbene quinones which are formed by this process are useful as dyes, germicides, and also as intermedaites in the synthesis of other organic com pounds and particularly in the synthesis of synthetic sex hormones, plant hormonesand plant growth regulators. These compounds are represented by the following structural formulae:

R1 2 t I R1 7 r? a sane R5 R .11 1 l -2. Rs 'M Tetra-alkylstilbene quinones can be reduced to form the corresponding 4,4-stilbene diols and a,u.'-dihydrostilbe ne diols which are useful as synthetic sex hormones and synthetic plant hormones. The tetra-alkylstilbene quinones and tetra-alkoxystilbene quinones are also reduced by catalytic hydrogenation at mild conditions to form dihydroxy tetra-alkylwr tetra-alkoxy)stil- -bene and dihydrostilbenes which are useful in the syntheses of other organic compounds. Thus 3,5,3,5' tetra alkyl stilbene quinone and 3,5,3?,5-tetra-alkoxy-stilbene quinone are hydrogenated to form 4,4'-dihydroxy-3,5,3,5- tetraalkylstilbene, 4,4 dihydroxy.-3,5,3 ,5 -tetraalkoxystilbene, a,a' -dih ydro-3,5,3' ,5 -tetra-alkylstilbene and a,a'-dihydro-3,5,3',5'-tetra-alkoxystilbene. v

The nature of the present invention is illustrated further by the following examples which should not be misconstrued to limit unduly the 7 generally broad scope of the invention.

Example I 22 grams of 2,6-di-tert-butyl-p-cresol was treated with 4 grams of sodium-chlorate in 150 ml. of an aqueous solution containing 2% by weight of sulfuric acid with 0.25 gram vanadium pentoxide as a catalyst at a temperature of (0-80" C. for a time of 5 hours, during which time the reaction mixture was stirred continuously. This treatment yielded a brick red compound which melted at atemperature of from between 286 and 296 C. This compound was found to be 3,5,3,5'-tetra-tert-butylstilbene quinone.

Example II.

In another run, a solution consisting of 200 ml. of pentane and 25 grams of 2,6-di-tert-butyl- 4-methylphenol was contacted with 100 ml. of an aqueous solution containing 10% by weight of sodium hydroxide. This mixture was stirred continuously at a temperature of 28 to 32 C. while an aqueous solution consisting of 400 ml. of water'and 104 grams of potassium ferricyanide was added thereto during a time of 20 minutes. This oxidation treatment also yielded a brick red material having about the same melting point as that referred to in Example I. The brick red compound had a relatively low solubility in cyclohexane and accordingly made it difiicult to obtain an accurate molecular Weight determination in this solvent. Nevertheless, the two values obtained, namely 437 and 566- each plus or minus 10% gave evidence that the main reaction occurring was a dimerization of the charged cresol to form tetra-tert-butyl-stilbene quinone.

The 3,5,3,5'-tetra-tert-butyl-stilbene qulnone so formed was soluble in concentrated sulfuric acid but had a relatively low solubility in benzene, carbon tetrachloride, acetone, acetic anhydride, and ethyl acetate. It was practically insoluble in concentrated hydrochloric acid and in Claisens solution.

When some of the 3,5,3,5'-tetra-tert-butylstilbene quinone was reduced with sodium in isoamyl alcohol the color changed from yellowishred through green to a blue-green. Also the 3,5,3,5-tetra-tert-butyl-stilbene quinone was reduced by stannous chloride to form the corresponding 4,4stilbenepdiol. The 3,5,3,5-tetratert-butyl-stilbene quinone also added hydrogen chloride in glacial acetic acid to form 4,4'-dihydroxy 11,0. dichloro 3,5,3,5 tetra tert butyl-stilbene having the following structural formula:

The catalytic reduction of 3,5,3',5-tetra-tertbutyl-stilbene quinone by hydrogen in ethyl acetate solution in the presence of palladium on barium sulfate at a temperature'of C. and at a pressure of 100 atmospheres produced a substantial amount of 4,4-dihydroxy-3,5,3,5'-tetratert-butyl-a,a'-dihydrostilbene having the structural formula:

(CHQQQ n n 0 (CH1):

-CH2'CH2- -on cam t 1 1 owns):

Erample HI Five grams of mesitol (2,4,6-trimethylphenol) was oxidized with 25 grams of silver oxide suspended in 350 ml. chloroform. This oxidation yielded a deep red colored compound with a melting point of 222 to 224 C. corresponding to that of synthetically prepared 3,5,3',5'-tetra-methylstilbene quinone and giving no melting point depression on a mixture of the red oxidation product and the synthetically prepared quinone.

The synthesis used for preparing 3,5,3',5- tetra-methylstilbene quinone consisted in treating 2,6-dimethylphenol with formaldehyde in 5% sodium hydroxide solution to yield 3,5-di-methyl 4-hydroxy-benzyl alcohol which was then treated with hydrogen bromide gas in chloroform to produce 3,5-di-methyll-hydroxy-benzy1 bromide. the. latter then being shaken in ether solution with'a concentrated solution of sodium bicarbonate to] form '3,5,3,5' tetramethylstilbene quinone." I

Example IV 20 grams of 2,4-di-methyl-6-tert-butyl-pheno1 were dissolved in 100 ml. of pentane and this solution was then contacted with 100 ml. of an Example V In a run similar to that described in Example IV, 2,6-di-tert-butyl-4-methyl-phenol was oxidized by potassium ferricyanide to produce an orange-red, colored dye which was useful for dyeing cloth and also for dyeing gasoline.

We claim as our invention:

1. A process for producing a tetra-substituted stilbene quinone in which the substituents are selected from the'members of the group consisting of an alkyl group and an alkoxy group each containing from one to six carbon atoms which comprises oxidizing a member of the group consisting of a dialkyl-p-cresol and a di-alkoxy-p cresol having alkyl and alkoxy groups containing from one to six carbon atoms by heating the same at a temperature of from about 20 to about 100 C. with an oxidizing agent selected from the group consisting of alkali metal chlorates and ferricyanides, lead dioxide and silver oxide.

2. A process for producing. a polyalkylstilbene quinone which comprises oxidizing a polyalkylphenol in which the alkyl groups contain from one to six carbon atoms by heating the same at a temperature of from about 20 to about 100 C. with an oxidizing agent selected from the group consisting of alkali metal chlorates and ferricyanides, lead dioxide and silver oxide.

3. A process for producing a tetra-alkylstilbene quinone which comprises oxidizing a 2,6- dialkyl-p-cresol having alkyl groups containing from one to six carbon atoms by heating the same at a temperature of from about 20 to about 100 C. with an oxidizing agent selected from the group consisting of alkali metal chlorates and ferricyanides, lead dioxide and silver oxide.

4. A process for producing tetramethylstibene quinone which comprises oxidizing 2,6-dimethylp-cresol by heating the same at a temperature of from about 20 to about 100 C. with an oxidizing agent selected from the group consiting of alkali metal chlorates and ferricyanides, lead dioxide and silver oxide.

5. A process for producing tetra-tert-butyl stilbene quinone which comprises oxidizing 2,6- di-tert-butyl-p-cresol by heating the same at a temperature of from about 20 to about 100 C. with an oxidizing agent selected from the group consisting of alkali metal chlorates and ferricyanides, lead dioxide and silver oxide.

6. A process for producing a tetraalkylstilbene quinone which comprises oxidizing a 2,6-dialkylp-cresol having alkyl groups containing from one to six carbon atoms by heating said cresol 6 with a mixture of an alkali metal chlorate and an aqueous solution of a mineral acid at a temperature of from about 20 to about 100 C.

7. A process for producing a tetraalkylstilbene quinone which comprises oxidizing a 2,6-dialkylp-cresol having alkyl groups containing from one to six carbon atoms by heating said cresol with a mixture of sodium chlorate and an aqueous solution of sulfuric acid at a temperature of from about to about C.

8. A process for producing tetramethylstilbene quinone which comprises oxidizing 2,6-dimethylp-cresol by heating said cresol with a mixture of sodium chlorate and an aqueous solution of sulfuric acid at a temperature of from about 70 to about 80 C.

9. A process for producing tetra-tert-butylstilbene quinone which comprises oxidizing 2,6-ditert-butyl-p-cresol by heating said cresol with a mixture of sodium chlorate and an aqueous solution of sulfuric acid at a temperature of from about 70 to about 80 C.

10. A process for producing a tetra-substitute stilbene quinone in which th substituents are selected from the members of the group consisting of an alkyl group and an alkoxy group each containing from one to six carbon atoms which comprises treating a member of the group consisting of a di-alkyl-p-cresol and a di-alkoxy-pcresol in which the alkyl and alkoxy groups contain from one to six carbon atoms with potassium ferricyanide and recovering from the resultant oxidation product a tetra-substituted stilbene quinone.

11. A process for producing a tetra-substituted stilbene quinone in which the substituents are selected from the members of the group consisting of an alkyl group and an alkoxy group each containing from one to six carbon atoms which comprises treating a member of the group consisting of a di-alkyl-p-cresol and a di-alkoxy-pcresol in which the alkyl and alkoxy groups contain from one to six carbon atoms with lead dioxide and recovering from the resultant oxidation product a tetra-substituted stilbene quinone.

12. A process for producing a tetra-substituted stilbene quinone in which the substituents are selected from the members of the group consisting of an alkyl group and an alkoxy group each containing from one to six carbon atoms which comprises treating a member of the group consisting of a di-alkyl-p-cresol and a di-alkoxy-pcresol in which the alkyl and alkoxy groups contain from one to six carbon atoms with silver oxide and recovering from the resultant oxidation product a tetra-substituted stilbene quinone.

WILLIAM K. T. GLEIM. ALEXANDER GAYDASCH. ROBERT E. ROSENWALD.

REFERENCES CITED The following references are of record in the file of this patent:

Yohe: Jour. Am. Chem. Soc. 69, 2644-2648, (1947). 

1. A PROCESS FOR PRODUCING A TETRA-SUBSTITUTED STILBENE QUINONE IN WHICH THE SUBSTITUENTS ARE SELECTED FROM THE MEMBERS OF THE GROUP CONSISTING OF AN ALKYL GROUP AND AN ALKOXY GROUP EACH CONTAINING FROM ONE TO SIX CARBON ATOMS WHICH COMPRISES OXIDIZING A MEMBER OF THE GROUP CONSISTING OF A DIALKYL-P-CRESOL AND A DI-ALKOXY-PCRESOL HAVING ALKYL AND ALKOXY GROUP CONTAINING FROM ONE TO SIX CARBON ATOMS ABOUT 20* TO ABOUT 100* C. WITH AN OXIDIZING AGENT SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL CHLORATES AND FERRICYANIDES, LEAD DIOXIDE AND SILVER OXIDE. 